adding entries to a /etc/export file

I need advise on how you would amend entries on a /etc/exports file via command line.   When i had an entry via using the exportfs -p, it overrides my entry, such as i have added the below entry :

exportfs -p rw=,root=

I Know want to remove the ip address from the root access, and add an IP   How can i write this without writing the whole command again.

Also after adding, do i need to run the exportfs -a command .

Re: adding entries to a /etc/export file

You can't. You will have to use some external processing to extract information, change it and replace the line again.

And yes, if you changed just /etc/exports, you will need to run "exportfs -a" (or just for this entry) to activate it.